Tag: Penetration probe.

When I started cooking sous vide, one year ago, I searched information about cooking times and temperatures on internet. Nothing was available at this time except Douglas Baldwin Practical Guide to Sous Vide. Therefore I purchased some books that were rated good or excellent on some online shops such as “Under Pressure – Cooking Sous Vide” of Thomas Keller and “Sous-Vide: Garen im Vakuum” of Viktor Stampfer. These books were nice with beautiful pictures…but not really containing relevant technical information. Above all, sous vide recipes of these books couldn’t be reproduced without a penetration probe. Then I realized that Douglas Baldwin’s Guide was the best source of information.

At the same time I heard about a book from Spanish cooks called Joan Roca and Salvador Brugués. But this book was available in Spanish only. This book is now available in English and French. The price of this book is crazy! I saw some online shop proposing it at USD 200! I bought mine in French language at EUR 110 incl. shipping.

The book is nice and full of technical information (100 pages of tech. information to be compared with 50 pages of recipes). I didn’t have time so far to read it completely but one think already disappointed me, you cannot find cooking tables such as Baldwin ones. If you want to cook with Joan Roca and Salvador Brugués cooking book then you need to purchase some turbigomme and a penetration probe…again. Anyway this book seems very interested and I’ll give you my feed back soon about it.

As you may already know Douglas Baldwin “Practical Guide to sous Vide Cooking” is to date probably one of the only serious source of information about sous vide that you can download for free on internet (English, Portuguese/Brazil, French and German). The revolution of this document is to allow home cooks cooking sous vide with tables. No need of an external probe to be inserted in the pouch in order to get the internal temperature of the food. Before using Baldwin tables I purchased most of the books available but none of them were mentioning the thickness of food as a key information in order to cook sous vide. Therefore, in my opinion, all these books can be considered as art books but not cooking books where recipes can be reproduced.

I have experimented Baldwin tables for a while now and I have to admit that I have never been sick or disappointed by the degree of doneness according to the temperatures given.

Nevertheless I realized that nobody on the net ever discussed if Baldwin tables are correct or not. Do I have to accept the fact that everybody is assuming these tables are accurate?

This the reason why I decided to purchase an external penetration probe and verify by myself. For those who would like to purchase such equipment I want to say that I made a mistake in my previous post when buying the needle probe from Thermoworks. The one that should be used for sous vide (water proof) is THS-113-181 only (see on the right of the picture). The needle is very thin (1 mm) and long enough to get inside a 7 cm thick beef fillet (incl. the turbigomme foam).

For my first test of Baldwin table I took a cut of salmon, 30 mm thick that I wanted to cook “mi-cuit” at 47°C. Douglas Baldwin table indicates 1 hour and 2 minutes cooking time. As mentioned in Baldwin document I raised the temperature of my immersion circulator of 0.5°C (47.5°C) in order to be sure to reach the target temperature of 47°C.

In order to comply totally with Baldwin table I took care the core temperature of the salmon was 5°C. This step made me realizing that my fridge is definitely not cold enough as the core temperature of my salmon was 10°C before chilling it! As illustrated on the picture I immersed the pouch in iced water for some minutes.

As mentioned above I set my immersion circulator at 47.5°C for 1:02 and noted frequently the data in order to make a graph out it.

And the result is EXCELLENT!

I was very surprised to see how fast the temperature was raising during the first minutes. I was also having some doubts when the countdown of my sous vide equipment was indicating 22 minutes left while the core temperature of the salmon was 36.6°C. The last tenth of degrees take really long to be reached and I now understand why you should set your sous vide appliance 0.5°C above the target temperature…if you don’t it will take ages before you really reach the target temperature.

A month ago I decided to purchase a digital thermomether with a penetration probe. I had a chock when looking at prices on internet. Price for such thermometer is usually in the range from EUR 200 to EUR 400.
Then, when I saw the Thermowoks onlineshop proposing a similarly equipment for approx. USD 110 incl. shipping to Europe…I decided very fast to make a try.

My worry was to determine how good this thermometer is. Was it well calibrated? I asked a friend of mine if he could find a precision thermometer in order to compare its precision to the Thermoworks one. Thanks to Bertrand.L I could find someone borrowing me the GMH-3710. He told me he purchased it here for approx? EUR 220 excl. VAT and shipping costs. This is 3 times the price I purchased mine!

I red on internet that temperature accuracy depends of the temperature. In other words, the higher the temperature is, the bigger the risk of inaccuracy could appear.

For the purpose of my test I tried with both the thermomethers to assess the temperature of an apple, a glass of water containeing water at 46°C and 79°C.

Above a picture of the GMH-3710

My test with an apple that was laying around in kitchen was excellent. The difference in temperature between the 2 thermometers was in the range from 0.1°C to 0.2°C only. Therefore the inside temperature of the apple was approx. 21.5°C.

The test with the 46°C water was also good with a difference of maximum 0.3°C.

I also made the test with a glass of water at 79°C. The difference of temperature was in the range from 0.3°C to 0.4°C.

To sum up : The Thermoworks digital thermometer seems to work very well and is price competitive. I am in a hurry to try it while cooking sous vide!